The U.S. Department of Energy's Lawrence Berkeley National Laboratory has developed nanoscale ropes that are capable of braiding themselves and enduring harsh conditions.

Ron Zuckermann, study leader and the Facility Director of the Biological Nanostructures Facility in the Lawrence Berkeley National Laboratory Molecular Foundry, and Rachel Segalman, a faculty scientist at Lawrence Berkeley National Laboratory and a professor of Chemical and Biomolecular Engineering at the University of California, Berkeley, along with a team of scientists, have created nanoscale ropes that have similar properties to biological materials. 

"The hierarchal self assembly is the hallmark of biological materials such as collagen, but designing synthetic structures that do this has been a major challenge," said Zuckermann.

Researchers created these nanoscale ropes by designing synthetic polymers that can assemble into more complicated structures all by themselves. The team began with a block copolymer, which is a polymer with two or more different monomers. 

"Simple block copolymers self assemble into nanoscale structures, but we wanted to see how the detailed sequence and functionality of bio-inspired units could be used to make more complicated structures," said Segalman. 

To do this, the team worked with bio-inspired polymers known as peptoids, which imitate peptides to produce proteins in nature. But the team wanted to use peptoids to produce synthetic structures that act like proteins.  

Zuckermann and his team then robotically synthesized, processed and added solution to the peptoid pieces to make them self assemble. What they ended up with were self-made structures and shapes with braided helices. The helix's ability to be controlled "atom-by-atom" as well as its hierarchal structure makes it so that it can be used as a "template for mineralizing complex structures on a nanometer scale." 

"These braided helices are one of the first forays into making atomically defined block copolymers," said Zuckermann. "The idea is to take something we normally think of as plastic, and enable it to adopt structures that are more complex and capable of higher function, such as molecular recognition, which is what proteins do really well." 

This type of research could potentially be used as scaffolds that direct the production of nanoscale wires, drug delivery vehicles that aim for a specific disease at the molecular scale, or to create molecular sensors that separate molecules. 

The next step is to take the control they have over the sequence of the structure and explore how tiny chemical changes adjust the helical structure. 

This study was published in the Journal of the American Chemical Society.